Spreadsheets and Security Don't Mix: A Real-World Look at What Can Go Wrong
For decades, spreadsheets have been the default tool for tracking everything from budgets to project timelines. Their flexibility and accessibility make them attractive to small and medium-sized enterprises that want a quick way to manage data without investing in specialized software. When it comes to security risk management, however, spreadsheets create more problems than they solve.
Managing security risks requires accuracy, collaboration, accountability, and the ability to respond quickly to change. Spreadsheets, by their very design, fall short in all of these areas. What looks like a simple, low-cost solution can actually expose organizations to mistakes, compliance failures, and serious incidents. The best way to understand the risks is to look at real-world examples—some drawn from public cases, others anonymized but based on common experiences across industries.
The Case of the Lost Risk Register
A mid-sized healthcare provider in Europe relied on Excel to track its information security risks. The spreadsheet was stored on a shared drive and updated manually by the IT manager. When a regulator launched an audit, the team scrambled to prepare. They quickly realized that no one had a consistent copy of the risk register. Different departments had downloaded versions over the years, each containing conflicting information. Some risks had been closed in one version but remained open in another. Others had disappeared altogether.
Compliance Failure:
The regulator determined that the organization could not provide an accurate history of how it identified and mitigated security risks. The result was a significant compliance penalty under GDPR. What seemed like a simple administrative task—keeping a spreadsheet updated—ended up costing the organization hundreds of thousands of euros and damaging its reputation.
This case highlights one of the biggest weaknesses of spreadsheets: version control. Without automated audit trails and centralized management, organizations cannot guarantee the integrity of their records.
The Formula Error That Hid a Critical Vulnerability
In another instance, an SME in the financial services sector used Excel to prioritize its cybersecurity risks. The register relied on a formula that multiplied the likelihood of a threat by its potential impact to generate a severity score. Unfortunately, a copy-paste error corrupted one of the formulas. A risk associated with weak multi-factor authentication was calculated as "low" instead of "high."
Critical Impact:
Because of this mistake, leadership decided to delay investments in upgrading the authentication system. Months later, attackers exploited the weakness in a phishing campaign that led to unauthorized access to customer data. The incident not only damaged client trust but also triggered costly remediation and notification requirements.
The organization eventually discovered the miscalculation, but by then the damage was done. This cautionary tale demonstrates how fragile spreadsheets can be. A single unnoticed formula error can change priorities, mislead decision-makers, and leave organizations vulnerable.
The Audit That Turned Into a Crisis
A manufacturing company preparing for ISO 27001 certification attempted to demonstrate its risk management process using spreadsheets. The auditors asked for evidence of how risks had been tracked, updated, and mitigated over time. The company produced a spreadsheet, but the auditors quickly noticed problems. There were no timestamps showing when changes had been made, no record of approvals, and no way to verify who had updated the document.
Certification Denied:
The auditors determined that the company could not prove that its risk management process was consistent or controlled. Certification was denied, and the business lost out on several lucrative contracts that required ISO compliance.
This story underscores another major flaw of spreadsheets: the lack of built-in governance. Without audit trails, access controls, or automated workflows, organizations cannot demonstrate compliance reliably. The hidden cost in this case was the loss of business opportunities tied directly to certification.
When Spreadsheets Become a Security Risk
Ironically, using spreadsheets to manage security risks can create new security problems of their own. In one anonymized example, a regional retailer tracked vulnerabilities in an Excel file that listed unpatched systems, weak configurations, and outdated applications. The spreadsheet was emailed back and forth between IT and compliance staff. At one point, an employee accidentally sent the file to an external vendor instead of an internal colleague.
Data Exposure Risk:
The document provided a detailed roadmap of exploitable weaknesses across the company's infrastructure. While the vendor was trustworthy and reported the mistake, the situation could have been disastrous. If the file had landed in the wrong hands, attackers would have gained insight into precisely where to strike.
This illustrates how the very act of managing sensitive data in spreadsheets can create a vulnerability. Password protection on files is weak, and once an attachment leaves the organization's control, it is nearly impossible to contain.
The Cost of Wasted Time
Not every cautionary tale involves a catastrophic breach. Sometimes the damage comes from inefficiency. A professional services firm used Excel to manage its security risk register, but updating the file became a full-time job for one employee. Every new risk required manual entry, every report required hours of formatting, and every update risked breaking formulas or formatting rules.
This scenario is common across SMEs. The hidden cost is not always an external fine or breach but the opportunity lost when talented staff spend their time babysitting spreadsheets instead of driving meaningful improvements in security.
Lessons From the Field
These examples—some headline-worthy, others quietly damaging—reveal a common pattern. Spreadsheets are brittle, error-prone, and poorly suited to the demands of modern security risk management. Organizations often learn this lesson the hard way, through failed audits, costly breaches, or wasted resources.
Moving Beyond Spreadsheets
The good news is that better options exist. Dedicated risk management platforms offer real-time collaboration, automated calculations, built-in compliance reporting, and robust security protections. They eliminate the version control nightmares, reduce the risk of errors, and ensure that sensitive data is handled securely.
Modern Platform Benefits:
- Real-time collaboration and updates
- Automated calculations and workflows
- Built-in compliance reporting
- Robust security protections
- Version control and audit trails
- Role-based access controls
For SMEs, the transition can feel daunting, particularly if spreadsheets have been the norm for years. But the risks of staying with the status quo are too great to ignore. Each cautionary tale above could have been avoided with the right tools in place.
Conclusion
Spreadsheets and security do not mix. While they may seem like a convenient starting point, their flaws become glaring over time. Lost risk registers, formula errors, failed audits, accidental disclosures, and wasted time are not just possibilities—they are realities faced by organizations around the world.
The real-world examples demonstrate that what appears to be a cost-effective solution can quickly become a liability. Organizations that recognize these patterns and invest in proper risk management tools will be better positioned to avoid the pitfalls that have caught so many others.